Optical Fiber Extrinsic Fabry-Perot Interferometric Sensor for Large-Strain Measurement

A design of the extrinsic Fabry-Perot interderometric (EFPI) optical fiber sensor for large-strain measurement is proposed and experimentally studied. The novel sensor with an air cavity was made by splicing a short section of collimation capillary with two standard single mode fibers with protective capillary. Experiments results showed that the sensor with an original cavity length of 100um has a large strain measurement of 200×10
⁶
με with a strain sensitivity of 44.3nm/με, and the linearity is up to 0.9995. This strain sensor also showed good repeatability and long times stability. Moreover, the simple manufacturing process without chemical etching, careful cleaving and special fusion. It can used for large strain sensing application with high precision and miniaturized size.